Self-aligned laser sight

Abstract: A laser sight 33, which is mounted in a recoil spring chamber 23 of a pistol 20, includes a battery power supply 34, a driver board 38 and a laser 27 in an elongated housing 10 and 11. The laser 27 is energized by lateral movements of a take-down latch 36. In a center position, insulation 46 in the middle of the latch 36 contacts a ball tip electrical contact 41 that extends through an end cap 35 of the elongated housing 10 and 11 and disconnects the laser 27 from the power supply 34. The end cap 35 mates with pre-existing features 26 of the recoil spring chamber 23 to self-align the sight.

Description: FIELD OF INVENTION This invention relates, in general, to laser sights for firearms, and, in particular, to laser sights that are mounted in chambers of firearms. BACKGROUND In my prior U.S. Patent 4,934,086, there is shown a firearm, in particular a pistol, in which a laser sight is mounted in a recoil spring guide chamber. Laser sights are often used by law enforcement authorities in order to enhance the negotiating position of a law enforcement officer when confronting a party subject to arrest. It is reported that once a party subject to arrest recognizes that the party has been targeted with a laser sight, such parties often cease further resistance to arrest and relinquish their own firearms. So, there is a need for a laser sight in such situations. Certain firearms are not equipped with safety latches. Law enforcement officers are trained to withdraw such a firearm from its holster and place a trigger finger along the recoil spring guide chamber of the firearm. Such technique reduces the cases of inadvertent firing of the firearm. However, it would be desirable to provide the law enforcement officer with a positive reinforcement for this training technique. There is also a need for a laser sight that may be quickly installed in a pistol without requiring substantial modification of the firearm. Until now, most laser sights for pistols have been accessories that are added by the pistol owner and not by the manufacturer. Such laser sight accessories often require substantial modification of the pistol in order to accommodate the laser sight. In some cases, the modification is so extensive that the pistol manufacturer will no longer honor the original warranty that was made in connection with the sale of the pistol. As such, it is desirable to have a laser sight accessory that requires minimal modifications of the pistol so that the original manufacturer warranty is maintained and so that the laser sight can be rapidly installed by the pistol owner or user without requiring installation by a trained technician. Until now, laser sights have required alignment after they are mounted on the firearms. Such alignment can be very time consuming and difficult for gun owners and requires a special rest to hold the firearm. Even if the alignment is originally accomplished by a trained technician, laser sights that are appended to the outside of firearms should be periodically tested to be sure that they have not been inadvertently knocked out of alignment. Accordingly, there is a need for the laser sights to be self-aligning and to require no adjustments after installation. There has also developed a need for a long lasting laser sight. Because current lasers require substantial power, laser sights have been of unduly large size in order to accommodate power supplies needed to maintain the laser in an operating condition for a reasonable amount of time, i.e., one hour or more. So, the users of laser sights have been faced with the dilemma of shrinking the size of the laser sight but reducing the overall operating life of the battery or having a larger sight that can accommodate a larger battery and thus a longer life. As such, there is a need for a relatively small laser sight with a small power source or battery that lasts for an hour or more. Summary The invention in its various embodiments described herein meets the needs expressed above. For example, a laser sight having a power source is disposed substantially entirely within the recoil spring guide chamber of a firearm, such as the recoil cavity of a pistol. The laser sight is itself contained in an elongated housing having at one end a window through which a laser beam is emitted and at the other end a battery cap. The elongated housing replaces the recoil spring guide that is normally mounted in the recoil chamber. The battery cap has several significant features. For one, it is shaped to mate with preexisting features of the recoil cavity. The engagement locks the elongated housing against rotation and restricts movement of the housing except in one direction along its axis, which is subsequently restrained by the recoil spring. For example, the battery cap can be formed with a key at its end to fit into a pre-existing slot in the recoil chamber. The key holds the rotational position of the housing so the laser sight can be preadjusted into a desired alignment with the firearm barrel. In addition, the fixed rotational position can be used to orient emitted beams having special shapes. Although oriented with respect to the elongated housing to hold alignment, the battery cap is removable to permit replacement of a battery pack within the housing. The battery cap is made of a insulating (i.e., non-conducting) material such as a soft polymer that is adapted to absorb the recoil shock transmitted by the recoil spring. A ball tip connector extends through the cap to establish an electrical connection with the battery pack. The take-down latch of the firearm (also referred to as a slide lock) is modified to turn the laser on and off. The take-down latch is made of a conducting metal but has a central insulating portion. The central portion electrically isolates the ball tip of the battery pack. However, moving the take-down latch to the left or right completes an electrical connection for turning on the laser. As such, when a law enforcement officer places his/her finger adjacent the trigger guard and on the take-down latch, a slight inward pressure on the take-down latch will turn on the laser and provide positive reinforcement for such safety procedure. The take-down latch can move either left or right in order to turn on the laser so as to accommodate either right-handed or left-handed users. Since the centered position is the off position for the laser, the take-down latch will automatically re-center itself and shut off the laser when inserted into a holster. That is, the sides of the holster will urge the take-down latch towards its center position thereby turning off the laser. Still another feature of the invention is that the driving circuitry of the laser is designed to operate the laser in a flashing mode of operation. This flashing mode of operation conserves the power of the laser while still providing a highly visible beam. Indeed, the flashing of the laser is chosen to be at a predetermined frequency that is most recognizable to the human eye. This frequency may be preferably between 8 and 12 Hz and is preferably at about a frequency of 10 Hz. This frequency is chosen so that the batteries in the laser are flashed at a predetermined rate and operated at a predetermined duty cycle, preferably between 10-20%, to permit the batteries to refresh themselves between laser flashes and to reduce the energy drain of the batteries. Drawings Figure 1 is a partially cut away view of a firearm having a laser sight mounted within the recoil chamber. Figure 2 is an exploded perspective view of the laser sight components added to the firearm. Figure 3 is a partial sectional view of the recoil chamber with the laser sight installed. Figure 4 is a view similar to Figure 3 without a laser sight. Figure 5 is a side view partial view of the barrel engaged with a modified take-down latch. Figure 6a-6d are orthogonal views of the take-down latch. Figure 7 is a combination electrical and mechanical schematic of the take-down latch and laser sight circuitry. Figures 8 and 9 are cross-sectional views of alternative embodiments of the take-down latch for other models of pistols. Figure 10 is an end view of an alternative embodiment of a battery cap that is used to align the laser sight in another model pistol. Figure 11 is a perspective view of the alternative battery cap. Detailed Description With reference to FIG. 1 there is generally shown a firearm 20. Typical of such a firearm is the Glock 17/17L/18/19/20/21 and 22 manufactured by Glock, GmbH of Austria and the Sigma 9 mm17/17L/18/22/24 manufactured by Smith & Wesson of Springfield, Massachusetts. The pistol 20 is a semi-automatic device. The pistol grip frame 21 holds a magazine 16 that contains a number of rounds of ammunition. The ammunition is spring biased in a direction toward a reciprocating firing chamber 22 (also referred to as a slide). Cartridges from spent rounds are ejected through ejection slot 15 when the reciprocating chamber 22 moves to the left or backward under recoil action following discharge. A barrel 25 extending from the reciprocating chamber 22 is connected to the pistol grip frame 21 via a modified take-down latch 36. Disposed beneath reciprocating chamber 22 is a recoil chamber 23. Within recoil chamber 23 is a laser sight 33 that replaces a conventional recoil spring guide rod. A recoil spring 32, which surrounds the laser sight 33, extends between an apertured projection 24 of the reciprocating chamber 22 at one end of the recoil chamber 23 and an annular seat 45 (FIG. 3) of the laser sight 33 at the other end of the recoil chamber 23. Turning to FIG. 2, there is shown the laser sight 33 which includes a battery pack 34 that sits in one end of a casing 11 of the laser sight 33 and is enclosed therein by a removable end cap 35 with a ball tip electrical contact 41. The cap 35 is made of insulating material, preferably a soft polymer capable of absorbing the recoil shock of the reciprocating chamber 22. The cap 35 has internal recesses that receive lugs 12 of laser sight casing 11 for rotationally orienting the cap 35 with respect to the casing 11. The original take-down latch, not shown, is replaced by the modified take-down latch 36 and a modified take-down latch spring 37. The spring 37 biases the latch 36 against a catch 19 (FIG. 5) of the barrel 25. The take-down latch 36 is generally made of a conducting metal but has a central insulating portion 46. In its normal centered position, the take-down latch 36 has its insulating portion 46 bearing against the ball tip electrical contact 41 of the cap 35 thereby interrupting the power to the laser sight 33 and maintaining the laser in an off condition. However, movement of the take-down latch 36 to either the right as indicated by arrow C or to the left as indicated by arrow D will bring the metallic or electrically conductive portion of the take-down latch 36 into contact with the ball tip 41 thereby completing the circuit through the battery pack 34 to power the laser 33. A lens housing 10 is press fit or otherwise suitably mounted on the casing 11. At one end there is a window 17. Set screws 9 adjust and align collimating lens assembly 8 contained in lens housing 10. In line with the window 17 and lens assembly 8 is a laser 27, such as a laser diode. Connected to the laser 27 is a driver board 38 that provides both electrical power and control to flash the laser 27. Driver board 38 includes suitable electronic circuitry, including an oscillator for operating the laser 27 at a predetermined frequency and for a predetermined duty cycle. The circuitry is preferably of complementary metal oxide (CMOS) design that has relatively low power consumption and a controllable duty cycle. Driver board 38 is connected via a wire spring 39 to the battery pack 34. The battery pack 34 is in turn connected to the ball tip 41 in the end cap 35 via another wire spring 40. With reference to FIGS. 3 and 4, the projection 24 of the reciprocating chamber 22 forms a partial closure at one end of the recoil chamber 23. The recoil spring 32 is compressed between the projection 24 and the annular stop 45 of the end cap 35. A bore 14 through the projection 24 journals the lens housing 10 with a slide fit that accommodates the reciprocating action of the projection 24. The bore 14 also forms an aperture through which a beam 28 of laser light is emitted from the recoil chamber 23. At the other end of chamber 23, there is a preexisting slot 26. A key portion 42 on the end cap 35 fits into the slot 26 to rotationally align the laser 33 within the recoil chamber 23. The set screws 9 are used to preadjust the beam 28 into a desired alignment with the barrel 25. Thereafter, the laser sight 33 can be reinserted into the recoil chamber 22 without adversely affecting the alignment or orientation of the beam 28. With reference to FIG. 7, the laser diode 27 has one end connected electrically and mechanically to the take-down latch 36 through the housing of laser sight 33, the recoil spring 32, and the recoil chamber 23. The other end of laser diode 27 is connected to the driver board 38, optional switch 47, the battery pack 34, and the ball tip contact 41. When the take-down latch 36 is in its normal or centered position, the insulated portion 46 of take-down latch 36 opens the electrical circuit between the battery pack 34 and laser diode 27. However, when the take-down latch 36 is moved either in the direction of arrow C or arrow D, i.e., to the left or to the right, then the ball tip 41 contacts metallic portion 48 of the take-down latch 36 and thereby establishes an electrical contact between the battery pack 34 and the laser 27. The driver board 38 has suitable electronic circuitry for flashing the laser 27 at a predetermined rate. The laser is flashed to prolong the life of the battery pack 34. The battery pack 34 preferably contains silver oxide or lithium batteries. Such batteries tend to refresh themselves between uses. Thus, the flashing of the laser diode 27 is also chosen to be at a frequency and duty cycle compatible with the refresh characteristic of the battery pack 34. Furthermore, the laser diode 27 is flashed at a frequency that is especially recognizable to the human eye. Such frequency is between 8 and 12 Hz and is preferably at approximately 10 Hz. By flashing on and off, the overall life of the silver oxide battery pack 34 is extended from a continuous use of about several minutes to an hour or more of flashing use. With reference to FIGS. 1 and 5., there is shown the modified take-down latch 36 coupled to catch 19 of the barrel 25. When the reciprocating chamber 22 is moved slightly in the direction of arrow A, i.e., to the rear, then the take-down latch may be moved in the direction of arrow B against the bias of spring 37. By holding the take-down latch 36 below the catch 19, the barrel 25 together with the reciprocating chamber 22 can be detached from the frame 21. With reference to FIGS. 6a-d, the take-down latch 36 is made from a steel blank. It is symmetrical about center line 7. Ridges 18 on both ends assist the user in manipulating the latch 36 horizontally and vertically. Insulating material 46 is disposed in the center of the latch 36 on face 6 that faces the ball tip contact 41. A rounded detent 5, which bears against the spring 37, keeps the latch 36 in position until the latch is manipulated by a user. Insulating material 46 fills a slot 4 and bore 3 that are machined into the metal latch 36. The material 46 is any suitable insulating material, preferably a moldable epoxy. Another slot 2 is machined to receive the catch 19 of the barrel 25. Those skilled in the art will appreciate further modifications, changes, additions, and omissions may be made to the above described embodiment which relates several different advances over the art that can be practiced individually or in combination. For example, the modification of the take-down latch as an on/off switch would be useful for controlling other electrical devices attached to the firearm, including other types of sighting devices. Those skilled in the art will also recognize that the key and the slot configuration may be reversed so that the reciprocating chamber 23 has a key and the cap 35 has a slot that accepts the key so long as such mating features prevent rotation of the laser sight 33. Other frequencies may be used to flash the laser in order to provide a highly recognizable beam and also prolong the life of the batteries. Other lasers may be adapted to the laser sight including a surface emitting laser that may not require a collimating lens. It is also within the skill of those in the art to apply the various advances to other firearms, including those having take-down latches of different configurations. For example, the take-down latch of a pistol made by Beretta or SIG would have a general cylindrical shape and be adapted to have ball detents on each end to hold the latch in its left or right position. See FIGS. 8 and 9 for examples of take-down latches compatible with such firearms. In FIG. 8, a take-down latch 50 is provided for a Sig Sauer pistol (not shown). The latch 50 has detents 51, 52 disposed on opposite ends. A center insulative portion 53 electrically uncouples the battery pack 34. External flanges 54, 55 are manipulated by the user's trigger finger to turn on the laser sight 33. A similar latch 60 for a Beretta pistol is shown in FIG. 9. There, ball type detents 61, 62 hold the latch 60 in place. Center portion 63 is made of insulating material and external flanges 64, 65 are used to move the latch 60 off center and turn on the laser 27. FIGS. 10 and 11 show an alternative end cap 70 for the Sig Sauer pistol. The end cap 70 has similar internal recesses 72 for receiving lugs 12 of laser sight casing 11 and an opening 74 for the ball tip electrical contact 41. However the cap is made with two differently shaped and positioned keys 76 and 78 that are designed to mate with preexisting features of the recoil chamber (not shown) of the SIG Sauer pistol. The cap 70 together with its keys 76 and 78 enables the laser sight to be preadjusted into a desired alignment with the firearm barrel and to be reinserted into the recoil chamber while preserving the alignment or orientation of the laser beam 28.

Claims: A firearm (20) comprising: a frame (21) supporting a reciprocating firing chamber (22), a barrel (25), and a recoil chamber (23) having an elongated cavity; a laser sight (33) surrounded by a recoil spring (32) within said cavity; said laser sight (33) having an elongated housing and a removable end cap (35); and said elongated housing containing a laser (27) and a battery (34) for powering said laser. The firearm of claim 1 in which said end cap (35) is made of an electrically insulating material. The firearm of claim 2 in which said elongated housing also contains an electrical contact that extends through said end cap (35) for completing an electrical connection between said laser and said battery. The firearm of claim 1 in which a window end of said laser sight (33) is slideable through a projection of said reciprocating firing chamber (22) and said recoil spring (32) extends between said projection of the reciprocating firing chamber (22) and said end cap (35). The firearm of claim 4 in which said end cap (35) includes an annular stop for engaging said recoil spring (32). The firearm of claim 1 in which said end cap (35) is replaceable in a predetermined orientation with respect to said elongated housing. The firearm of claim 1 in which said end cap (35) is shaped to lock said laser sight (33) against rotation for orienting said laser sight with respect to said barrel (25). The firearm of claim 7 in which said second and third directions are opposite directions. The firearm of claim 7 in which said electrical circuit includes a battery and drive circuitry that flashes said laser sight within a duty cycle that prolongs the life of said battery. A firearm (20) comprising: a frame (21) supporting a reciprocating firing chamber (22), a barrel (25), and a recoil chamber (23) having an elongated cavity; a laser sight (33) surrounded by a recoil spring (32) within said cavity; a first end of said laser sight (33) being slideable through a projection of said reciprocating firing chamber (22) and a second end of said laser sight being supported by mating features of said recoil chamber (23); and said second end of the laser sight being shaped to lock said laser sight against rotation for orienting said laser sight with respect to said barrel. The firearm of claim 10 in which said laser sight includes an elongated housing and an end cap (35) that forms said second end of the laser sight. The firearm of claim 11 in which said recoil spring (32) extends between said projection of the reciprocating firing chamber (22) and said end cap (35). The firearm of claim 12 in which said end cap (35) includes an annular stop for engaging said recoil spring (32). The firearm of claim 11 in which said end cap (35) is removable and replaceable in a predetermined orientation with respect to said elongated housing. The firearm of claim 14 in which said end cap (35) is made of an electrically insulating material. The firearm of claim 15 in which said elongated housing contains a laser (27) and a battery (34) for powering said laser. The firearm of claim 16 in which said elongated housing also contains an electrical contact that extends through said end cap for completing an electrical connection between said laser (27) and said battery (34).

Inventors: HOUDE-WALTER WILLIAM R, HOUDE-WALTER, WILLIAM R.
Applicants: LASERMAX INC, LASERMAX, INCORPORATED
Application year: 1994
Main classification: F41G1
IPC codes: F41G1